Presently, for performance reasons, the runtime linker ignores event disabling. The controlling process should not assume that a given break-point can not be reached because of the last
call to this routine.

rd_event_addr()

This function
specifies how the controlling program is notified of a given event.

Depending on the event type, the notification of the controlling process takes place by calling a benign, cheap system call that is identified by notify->u.syscallno,
or executing a break point at the address specified by notify->u.bptaddr. The controlling process is responsible for tracing the system call or place the actual break-point.

When an event has occurred, additional information can be obtained by this interface, defined in rtld_db.h.